Operative ubiquitin-specific protease 22 deubiquitination confers a more invasive phenotype to cholangiocarcinoma

Liquidambaric acid inhibits cholangiocarcinoma progression by disrupting the STAMBPL1/NRF2 positive feedback loop

BACKGROUND

Abnormal antioxidant capacity in cancer cells is intimately linked to tumor aggressiveness. Modulating oxidative stress status and inhibiting ferroptosis represents a novel anticancer therapeutic strategy. STAM Binding Protein Like 1 (STAMBPL1), a deubiquitinase, is implicated in various malignancies, yet its function in inhibiting ferroptosis and therapeutic potential for cholangiocarcinoma (CCA) remains unexplored.

PURPOSE

This study elucidates STAMBPL1's function in ferroptosis and evaluates liquidambaric acid (LDA) as its inhibitor for therapeutic applications.

METHODS

Using bioinformatics, WB, IHC, the expression and prognostic value of STAMBPL1 in CCA tissue was detected. The carcinogenic capacity of STAMBPL1 and LDA were assessed through CCK-8, EdU, cloning, transwell, scratch, apoptosis, and cell cycle assays. Flow cytometry and fluorescence microscopy, as well as transmission electron microscopy (TEM), examines the effects of STAMBPL1 and LDA on intracellular reactive oxygen species (ROS) and changes in mitochondrial membrane potential. The tumorigenic ability of STAMBPL1 and LDA in vivo was evaluated through subcutaneous tumor model and lung metastasis model. The underlying mechanism of STAMBPL1 was explored using immunoprecipitation coupled with Mass spectrometry (IP/MS), Co-immunoprecipitation (Co-IP), GST pull-down, DNA pull-down, and Dual-luciferase reporter assays. Molecular docking simulations, SPR, DARTS and CETSA predict the putative binding site of LDA on STAMBPL1 protein. Rescue experiments further confirmed the above conclusions.

RESULTS

This study unveils the upregulation and oncogenic role of STAMBPL1 in CCA. Functionally, STAMBPL1 notably enhances CCA cell proliferation and metastasis while impeding ferroptosis. STAMBPL1 stabilizes NRF2, a pivotal regulator of antioxidant enzymes, through K63 deubiquitination. Elevated NRF2, stabilized by STAMBPL1 overexpression, triggers GPX4 activation and reactive oxygen species (ROS) elimination. Particularly, sites 251-436 of STAMBPL1 interact with sites 228-605 of NRF2, facilitating DUB activity and eliminating ubiquitin molecules attached to NRF2, thus protecting it from proteasome-mediated degradation. Moreover, NRF2, acting as a transcription factor, binds to the promoter region of STAMBPL1 and activates its transcription, thus forming STAMBPL1/NRF2 positive feedback loop and regulating redox homeostasis. Molecular docking and in vitro/in vivo experiments identified that LDA binds to and inhibits STAMBPL1, thereby disrupting the STAMBPL1/NRF2 positive feedback loop, consequently suppressing CCA progression.

CONCLUSION

This study firstly reveals that STAMBPL1 promotes cholangiocarcinoma progression by upregulating NRF2, indicating that targeting the STAMBPL1/NRF2 axis is a novel therapeutic strategy. Additionally, our findings firstly suggest that LDA can bind to STAMBPL1, inhibiting NRF2 deubiquitination and offering significant therapeutic potential.

Quercetin prevents the USP22-Snail1 signaling pathway to ameliorate diabetic tubulointerstitial fibrosis

Our previous studies have demonstrated that ubiquitin-specific peptidase 22 (USP22) has the capacity to accelerate renal epithelial-to-mesenchymal transition (EMT) and promote the pathological progression of diabetic tubulointerstitial fibrosis (TIF) by regulating the ubiquitination of Snail1, an EMT transcription factor. Quercetin is a type of flavonol compound widely found in fruits and vegetables that has anti-inflammatory, antioxidant and anti-fibrosis effects. However, whether quercetin promotes the degradation of Snail1 and regulates the pathological progression of TIF by inhibiting USP22 requires further investigation. In this study, we found that quercetin significantly inhibited the expression of USP22 and Snail1 in high glucose (HG)-induced renal tubular epithelial cells (TECs), and reversed the expression of EMT-related proteins and inhibited the overproduction of fibronectin (FN) and Collage Type IV (Collagen IV) induced by high glucose. Additionally, quercetin blocked the deubiquitination of Snail1 mediated by USP22. Further study found that quercetin inhibited the interaction between USP22 and Snail1, thereby reducing the stability of Snail1. Furthermore, quercetin also reduced the protein levels of USP22 and Snail1 in the kidney tissue of diabetic mice and ameliorated renal function, delayed EMT and TIF. In conclusion, quercetin regulates the USP22-Snail1 signal pathway to inhibit the occurrence of EMT both in vitro and in vivo, and ultimately ameliorate the pathological progress of TIF.

Mogrol-mediated enhancement of radiotherapy sensitivity in non-small cell lung cancer: a mechanistic study

This study investigated mogrol's impact on non-small cell lung cancer (NSCLC) radiosensitivity and underlying mechanisms, using various methods including assays, bioinformatics, and xenograft models. CCK-8, clonogenic, flow cytometry, TUNEL, and Western blot assays evaluated mogrol and radiation effects on NSCLC viability and apoptosis. Ubiquitin-specific protease 22 (USP22) expression in NSCLC patient tissues was determined by RT-qPCR and Western blot. A xenograft model validated mogrol's effects on tumor growth. Bioinformatics identified four ubiquitin-specific proteases, including USP22, in NSCLC. Kaplan-Meier analysis confirmed USP22's value in lung cancer survival. Human Protein Atlas (HPA) database analysis indicated higher USP22 expression in lung cancer tissues. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis implicated ERK1/2 in NSCLC progression, and molecular docking showed stability between mogrol and ERK1/2. Further in vivo and in vitro experiments have demonstrated that mogrol enhances the inhibitory effect of radiation on NSCLC cell viability and clonogenic capacity. Cell viability and clonogenic capacity are reduced by >50%, and an increase in cellular apoptosis is observed, with apoptotic levels reaching 10%. USP22 expression was significantly elevated in NSCLC tissues, particularly in radiotherapy-resistant patients. Mogrol downregulated USP22 expression by inhibiting the ERK/CREB pathway, lowering COX2 expression. Mogrol also enhanced radiation's inhibition of tumor growth in mice. Mogrol enhances NSCLC radiosensitivity by downregulating USP22 via the ERK/CREB pathway, leading to reduced COX2 expression.NEW & NOTEWORTHY Mogrol enhances non-small cell lung cancer (NSCLC) cell sensitivity to radiotherapy by downregulating USP22 through the ERK/CREB pathway, reducing COX2 expression. These findings highlight mogrol's potential as an adjunct to improve NSCLC radiotherapy and open avenues for further research and clinical applications.

miR-99b/let-7e/miR-125a cluster suppresses pancreatic cancer through regulation of NR6A1

This experiment investigates how the miR-99b/let-7e/miR-125a cluster regulates the mechanism of NR6A1 involved in the invasive and metastatic effects of pancreatic cancer (PCa). Bioinformatics prediction and dual luciferase reporter gene assay were applied to verify the targeted relationship between miR-99b/let-7e/miR-125a and NR6A1. ASPC1 cells underwent transfection with lentiviruses to overexpress miR-99b/let-7e/miR-125a (individual or together) to explore functions of miR-99b/let-7e/miR-125a cluster governing NR6A1 in PCa. The detection of tumorigenesis was verified by tumor formation assay in nude mice in vivo, and mouse models of liver metastasis of PCa observed cell metastasis of PCa. MiR-99b/let-7e/miR-125a cluster was screened for differential expression in PCa. NR6A1 was confirmed as a target gene of the miR-99b/let-7e/miR-125a cluster. Findings demonstrated that overexpression of the miR-99b/let-7e/miR-125a cluster inhibited cell invasion, metastasis, proliferation, and tumorigenesis in PCa. Conversely, overexpressed NR6A1, a crucial gene in the miR-99b/let-7e/miR-125a cluster, promoted cell invasion, migration, and proliferation in PCa. Moreover, the overexpression of the miR-99b/let-7e/miR-125a cluster inhibited liver metastases and tumor formation. Thus, the study concludes that the miR-99b/let-7e/miR-125a cluster impedes the invasion and metastasis of PCa cells via targeting the NR6A1 gene.

Discovery of selective and potent USP22 inhibitors via structure-based virtual screening and bioassays exerting anti-tumor activity

Ubiquitin-specific protease 22 (USP22) plays a prominent role in tumor development, invasion, metastasis and immune reprogramming, which has been proposed as a potential therapeutic target for cancer. Herein, we employed a structure-based discovery and biological evaluation and discovered that Rottlerin (IC50 = 2.53 μM) and Morusin (IC50 = 8.29 μM) and as selective and potent USP22 inhibitors. Treatment of HCT116 cells and A375 cells with each of the two compounds resulted in increased monoubiquitination of histones H2A and H2B, as well as reduced protein expression levels of Sirt1 and PD-L1, all of which are known as USP22 substrates. Additionally, our study demonstrated that the administration of Rottlerin or Morusin resulted in an increase H2Bub levels, while simultaneously reducing the expression of Sirt1 and PD-L1 in a manner dependent on USP22. Furthermore, Rottlerin and Morusin were found to enhance the degradation of PD-L1 and Sirt1, as well as increase the polyubiquitination of endogenous PD-L1 and Sirt1 in HCT116 cells. Moreover, in an in vivo syngeneic tumor model, Rottlerin and Morusin exhibited potent antitumor activity, which was accompanied by an enhanced infiltration of T cells into the tumor tissues. Using in-depth molecular dynamics (MD) and binding free energy calculation, conserved residue Leu475 and non-conserved residue Arg419 were proven to be crucial for the binding affinity and inhibitory function of USP22 inhibitors. In summary, our study established a highly efficient approach for USP22-specific inhibitor discovery, which lead to identification of two selective and potent USP22 inhibitors as potential drugs in anticancer therapy.

USP32 deubiquitinase: cellular functions, regulatory mechanisms, and potential as a cancer therapy target

An essential protein regulatory system in cells is the ubiquitin-proteasome pathway. The substrate is modified by the ubiquitin ligase system (E1-E2-E3) in this pathway, which is a dynamic protein bidirectional modification regulation system. Deubiquitinating enzymes (DUBs) are tasked with specifically hydrolyzing ubiquitin molecules from ubiquitin-linked proteins or precursor proteins and inversely regulating protein degradation, which in turn affects protein function. The ubiquitin-specific peptidase 32 (USP32) protein level is associated with cell cycle progression, proliferation, migration, invasion, and other cellular biological processes. It is an important member of the ubiquitin-specific protease family. It is thought that USP32, a unique enzyme that controls the ubiquitin process, is closely linked to the onset and progression of many cancers, including small cell lung cancer, gastric cancer, breast cancer, epithelial ovarian cancer, glioblastoma, gastrointestinal stromal tumor, acute myeloid leukemia, and pancreatic adenocarcinoma. In this review, we focus on the multiple mechanisms of USP32 in various tumor types and show that USP32 controls the stability of many distinct proteins. Therefore, USP32 is a key and promising therapeutic target for tumor therapy, which could provide important new insights and avenues for antitumor drug development. The therapeutic importance of USP32 in cancer treatment remains to be further proven. In conclusion, there are many options for the future direction of USP32 research.

USP22 Contributes to Chemoresistance, Stemness, and EMT Phenotype of Triple-Negative Breast Cancer Cells by egulating the Warburg Effect via c-Myc Deubiquitination

BACKGROUND

Ubiquitin-specific protease 22 (USP22) has been implicated in the progression of breast cancer, while its regulatory functions in triple-negative breast cancer (TNBC) have been rarely reported. This study aimed to elucidate the effect and mechanism of USP22 on the malignant phenotype of TNBC cells.

MATERIALS AND METHODS

The expression of USP22, stemness genes, and EMT-related markers were analyzed by RT-qPCR and/or Western blotting. Cell stemness was determined by cell spheroid formation, flow cytometry for CD44+/CD24-, and extreme limiting dilution analysis. Cell proliferation and cisplatin (DDP) chemoresistance of TNBC cells were assessed by CCK-8 assay and xenograft model. Glycolysis was measured by Seahorse assay. The mechanism underlying the role of USP22 was explored by Co-immunoprecipitation, ubiquitination assay, and cycloheximide-chase analysis.

RESULTS

USP22 expression was positively correlated with DDP resistance in TNBC patients and cells. The proliferation, spheroid number, CD44+/CD24- cells, the expression of stemness genes and EMT-related markers in TNBC cells were significantly elevated after USP22 was overexpressed; however, these parameters in DDP-resistant TNBC (TNBC/DDP) cells were significantly reduced after silencing USP22. USP22 overexpression enhanced the extracellular acidification rate, proliferation, spheroid number, CD44+/CD24- cell number, and the expression of stemness genes and EMT-related markers in TNBC/DDP cells, while these effects were restrained by glycolysis inhibitors. Mechanically, USP22 interacted with c-Myc to promote its stabilization by deubiquitination in TNBC cells. Silencing of USP22 increased DDP sensitivity and survival of mice bearing TNBC.

CONCLUSION

USP22 contributes to chemoresistance, stemness, and EMT phenotype of TNBC cells by suppressing the glycolysis via c-Myc deubiquitination.

Down-regulation of USP22 reduces cell stemness and enhances the sensitivity of pancreatic cancer cells to cisplatin by inactivating the Wnt/β-catenin pathway

OBJECTIVE

Pancreatic cancer (PC) has the worst prognosis of all common cancers worldwide. This study was intended to investigate the role of ubiquitin specific peptidase 22 (USP22) in cisplatin sensitivity of PC cells and its regulatory mechanism.

METHODS

The expression of USP22 and the toxicity of cisplatin to PC cells were detected. The two cell lines AsPC-1 and CAPAN-1 with the most differential drug resistance were selected. By down-expressing USP22 in CAPAN-1 cells and over-expressing USP22 in AsPC-1 cells, the survival rate of PC cells treated with cisplatin was detected. The mRNA expressions of stem cell markers, cell stemness, migration ability and apoptosis of PC cells were detected. The expression of Wnt/β-catenin pathway related proteins was detected. The role of the Wnt/β-catenin pathway in PC cell stemness and cisplatin sensitivity was explored after adding the inhibitor HLY78 and activator DKK1.

RESULTS

USP22 was highly-expressed in PC cells, and the sensitivity of PC cells to cisplatin was negatively-correlated with USP22 expression. Downregulation of USP22 raised the sensitivity of PC cells to cisplatin, reduced the levels of stem cell markers, reduced the tumor sphere formation and migration, and promoted apoptosis. Silencing USP22 inhibited the Wnt/β-catenin pathway. Inhibition of USP22 reduced the cell stemness and augmented the sensitivity of PC cells to cisplatin by inhibiting the Wnt/β-catenin pathway.

CONCLUSION

Silencing USP22 can inhibit the Wnt/β-catenin pathway to reduce cell stemness and enhance the sensitivity of PC cells to cisplatin.

USP22 regulates lipidome accumulation by stabilizing PPARγ in hepatocellular carcinoma

Elevated de novo lipogenesis is considered to be a crucial factor in hepatocellular carcinoma (HCC) development. Herein, we identify ubiquitin-specific protease 22 (USP22) as a key regulator for de novo fatty acid synthesis, which directly interacts with deubiquitinates and stabilizes peroxisome proliferator-activated receptor gamma (PPARγ) through K48-linked deubiquitination, and in turn, this stabilization increases acetyl-CoA carboxylase (ACC) and ATP citrate lyase (ACLY) expressions. In addition, we find that USP22 promotes de novo fatty acid synthesis and contributes to HCC tumorigenesis, however, this tumorigenicity is suppressed by inhibiting the expression of PPARγ, ACLY, or ACC in in vivo tumorigenesis experiments. In HCC, high expression of USP22 positively correlates with PPARγ, ACLY or ACC expression, and associates with a poor prognosis. Taken together, we identify a USP22-regulated lipogenesis mechanism that involves the PPARγ-ACLY/ACC axis in HCC tumorigenesis and provide a rationale for therapeutic targeting of lipogenesis via USP22 inhibition.

Different deubiquitinases are associated to cancer development. Here, the authors show that PPARgamma is stabilized by USP22-mediated deubiquitination leading to lipid accumulation and promoting hepatocellular carcinoma.